Generally, in a clutch for automobile etc., a facing at an outer periphery of an output side clutch disc is pressed or released by and between a flywheel receiving an engine torque and a pressure plate, so that an engine power is transmitted or cut off therebetween. Consequently, temperature rise occurs in the pressure plate and the facing to cause a deformation of a friction surface of the pressure plate, and an early wear and a fade phenomenon etc. of the facing. To cope with these troubles, various cooling mechanisms supplying cooling air to friction elements of the pressure plate and the facing from outside of the clutch cover have been proposed. In these mechanisms, however, the pressure plate is cooled by induced air so that a relative velocity with outside air utilizing a rotation of clutch can not be utilized positively to cause an insufficiency in cooling. Further, when a diaphragm spring is used for the pull-type clutch, a stud pin for supporting the diaphragm spring to a clutch cover becomes disused so that a separate locking mechanism for the diaphragm spring is required. Moreover, when a clutch cover assembly including no clutch disc is transported for delivery from a clutch manufacturer to an automobile manufacturer or stored therein as a stock in a position where the pressure plate is hung downward, the pressure plate will swung due to its weight or vibration so that a strap plate connecting the pressure plate to the clutch cover will be excessively bent or deformed in an extreme case. For this reason, separate clamping members (such as spacers, bolts etc.) for clamping the pressure plate have conventionally been assembled thereto for avoiding the foregoing troubles during transportation or storing of a unit of the clutch assembly. However, this method has required additional labors in removing the clamping members from the pressure plate when it is assembled to an automobile and in previously attaching the clamping members to the pressure plate.